Solar Freaks

Yep, that sounds like the way to probably go.

Now all you need is a well designed, not too heavy (obviously the lighter the better) and mechanically and aerodynamically sound car. A panel with a half decent fill factor may also be useful, but that's another story.

If you can get all of that in order, you should be very difficult to beat.

miseli

We have two panels to choose from at the moment, they both have similar fill factors but one is 6.1W and the other 6.3W. Which one would you recommend using?

The higher the fill factor the better. These days, we have panels achieving fill factors of 0.78 and more.

A high fill factor will benefit you for anything above 50% light, as they are testing at half sun.

Anything below 50% light, and a lower fill factor is better.

The fill factors are almost identical, only 1% difference.

What are the fill factors?
And how were they measured?

um the from memory the fill factors are .77 and .78, measured at last years Western Australia Competition, with light box.

Also, with regards to the Firmware update I'd have to get the All Clear from my school before I did we did anything on behalf of them however I shouldn't see it being a problem. I'll have to get back to you on that one as soon as i hear word.

Conits

As Tony mentioned a post or 2 ago, the different fill factors have their advantages and disadvantages in different conditions. This is however assuming that a good FF panel corresponds to a low panel series resistance. This is however not always the case and so the panel series-parallel resistance balance is actually what needs to be looked at.

It really is becoming a bit of a juggling act these days with choosing a panel. Particularly now that you can't even change panels between days at the nationals.

In terms of panel power, the closer that you can get to 6 watts without going under is "technically" the most efficient (provided that your car is not too heavy) if you're looking at it from a "watts per kg" point of view. This however does not tell the whole story so don't be fooled. Below is a chart that was made up for the older rules before the extra weight for electronics was included in 2009.



A less powerful panel will mean that you will be carrying less weight and will therefore reduce your rolling resistance and stresses on the car, and also allow for lighter car construction. It will also be easier on the wallet.

Too close to 6W and you happen to get a low power reading at an event (unlikely these days now that panels are measured at 50%) and you will only disadvantage yourself.

miseli

It's interesting what you say about the way the panels are checked. Do you think it would then be better to go with 6.3W incase 6.1W is cutting it fine? Especially considering it means more efficient electronics?

yeah - i have graphed something similar based soley on ballast:weight. Of course there is an advantage to this on paper with using no maximiser, however am I right to assume talking the Maximiser's effects into account will overcome this advantage?

Conits

You need to remember that a higher powered car is less prone to the effects of wind resistance.
What i mean is.. The more power you have, the easier it is to cut through the wind.
Assuming, the 6W car and the 10W car had the same drag.